He has been detained in a prison on the city outskirts since. Megan returned to Britain on Saturday.

A European arrest warrant for child abduction had been issued on Sept 25 following a request by police in Britain. Mr Forrest from Ringmer, East Sussex, told Bordeaux's Appeals Court yesterday that he would not contest the warrant.

The judge said that meant that if his extradition went ahead, the British judicial system could only charge him for child abduction.

His lawyer, Daniel Lalanne said afterwards that he could only be charged with other offences "if he voluntarily agreed to do so".

The decision on his extradition will be given in court tomorrow. Until then, Mr Forrest remains in jail.

Megan was a prolific user of Twitter before she disappeared.

It is alleged she exchanged messages with her maths teacher on Twitter for at least six months, each posting cryptic messages and song lyrics about being in love.

Mr Forrest disclosed that he was “sacrificing his sanity” to be with the one he loved and described feeling “helpless”.

In March, when she was just 14, Megan claimed that she was “probably just infatuated” before adding two days later: “Age is overrated.”

The pair, who also discussed running away together.

Friends claimed that they alerted teachers at Bishop Bell School in Eastbourne when Megan and Mr Forrest, who is married, were seen holding hands on a flight home from a school trip to Los Angeles in February.

But questions have been raised about what action, if any, was subsequently taken.